In the page editor switch to HTML mode and wrap each section of content around divs you want to be a column.
<div class="col2w col2a">Col 1</div>
<div class="col2w col2b">Col 2</div>
<div class="col3w col3a">Col 1</div>
<div class="col3w col3b">Col 2</div>
<div class="col3w col3c">Col 3</div>
Next use CSS to style them to look like columns.